Gray wolves are known to
snack on blueberries, but the animals do more than fill their own bellies. A new,
serendipitous observation shows an adult wolf regurgitating the berries for its
pups to eat, the first time anyone has documented this behavior.
Wolves have a well-earned
reputation as skillful hunters with a taste for large, hoofed ungulates like
deer and moose. But scientists are increasingly recognizing that these
predators have an exceptionally varied diet, partaking in everything from
beavers and fish to fruit.
In 2017, biologist Austin
Homkes of Northern Michigan University in Marquette got a sense of just how
important this mixed diet could be for wolves. A cluster of signals from a GPS
collar on a wolf led Homkes to a meadow just outside Minnesota’s Voyageurs
National Park. Homkes, who was studying the animals’ predatory and dietary
habits, thought he was headed for a spot where the wolf had killed a meal. But
it turned out to be a rendezvous site, with adult wolves bringing food to their
no longer den-bound pups.
Homkes watched from a
distance as several pups gathered around an adult wolf, licking up at its
mouth. This behavior stimulates adult wolves to throw up a recent meal. Sure
enough, the adult began vomiting, and the pups eagerly ate what accumulated on
the ground. After the wolves left, Homkes got closer and saw that the
regurgitated piles were purely of partially chewed blueberries, he and colleagues report February 11 in the Wildlife
“It’s a pretty big part of
wolf ecology that was right under our noses that we didn’t see,” Homkes says.
Until now, he and his
colleagues thought pups in the region just casually munched on berries while
hanging around rendezvous sites, which often contain blueberry plants. The
fruit may be an underappreciated food source for the pups, the researchers
Conservation biologist Robert Mysłajek of the University of Warsaw says the discovery is an “interesting complement” to our knowledge of the species. “Such observations should be especially important for wildlife managers, who often focus only on wolf-ungulate interactions, forgetting about other food items consumed by wolves,” Mysłajek says.
The findings are generating plenty of questions. Homkes is curious about the nutritional value of blueberries for the mostly carnivorous wolves, and the consequences of a bad berry year. “What happens when blueberries are not available if a pack is used to relying on them?” he wonders.